Lid for sample holder

ABSTRACT

A lid for a sample holder that includes a load port, a first flow channel, and a second flow channel. The first flow channel includes a first end connected to the load port and a second end that opens into a first reservoir of the sample holder. The second flow channel also includes a first end connected to the load port and a second end that opens into a second reservoir of the sample holder.

This application is a U.S. National Phase Application of InternationalApplication No. PCT/US02/25722 filed Aug. 13, 2002, which claimspriority to U.S. application Ser. No. 09/930,099 filed Aug. 14, 2001,now U.S. Pat. No. 6,626,051, all of which are hereby incorporated byreference in their entirety.

BACKGROUND

1. Field of the Invention

The present invention relates to sample holders. More particularly, thepresent invention relates to a lid for sample holders.

2. Description of the Related Art

Various tests, reactions, and assays in biology, chemistry, clinicaldiagnostics, and other areas are performed in sample holders havingmultiple reservoirs designed to retain various samples and/or solutions.One type of sample holder is a microtiter plate having multiple wells inwhich separate tests, reactions, and assays can be performed.

Microtiter plates have a number of wells arranged in variousconfigurations. They typically come in standard sizes, such as 96 wellsarranged in 8 rows and 12 columns, 12 wells arranged in 3 rows and 4columns, and 384 wells arranged in 16 rows and 24 columns. However,microtiter plates can have any number of wells and the wells can bearranged in any configuration. Accordingly, the wells need not bearranged in columns and rows.

Some conventional covers for microtiter plates include a film thatcovers the entire microtiter plate. A disadvantage of these conventionalcovers is that a portion of the film must be removed from the microtiterplate in order to access and introduce materials into a single well,thereby exposing the well and surrounding wells to the environment andto each other. Exposing the wells in this manner can increase thepotential for contamination of the contents of the wells and thesurrounding environment.

Some conventional covers for microtiter plates include a lid that coverseach well of the microtiter plate. A disadvantage of these conventionalcovers is that each lid must be removed separately to introduce materialinto multiple wells, which can be time and labor intensive.Additionally, when a lid is removed, contamination of the contents ofthe well and the surrounding environment can still occur.

SUMMARY

The present invention relates to a lid for a sample holder and a methodof distributing fluid into the sample holder using the lid. In oneembodiment of the present invention, a lid for a sample holder includesa load port and a first flow channel and a second flow channel. Thefirst flow channel includes a first end connected to the load port and asecond end that opens into a first reservoir of the sample holder. Thesecond flow channel also includes a first end connected to the load portand a second end that opens into a second reservoir of the sampleholder.

DESCRIPTION OF THE DRAWING FIGURES

The present invention can be best understood by reference to thefollowing description taken in conjunction with the accompanying drawingfigures, in which like parts may be referred to by like numerals:

FIG. 1 is a top view of a microtiter plate;

FIG. 2 is a cross-sectional view of the microtiter plate in FIG. 1;

FIG. 3 is a perspective view of an exemplary embodiment;

FIG. 4 is a top view of the embodiment in FIG. 3;

FIG. 5 is a cross-sectional view of another exemplary embodiment;

FIG. 6 is a cross-sectional view of a portion of the embodiment in FIG.5;

FIG. 7 is a cross-sectional view of another portion of the embodiment inFIG. 5;

FIG. 8 is a cross-sectional view of still another exemplary embodiment;

FIG. 9 is a cross-sectional view of the embodiment in FIG. 8;

FIG. 10 is a cross sectional view of a portion of yet another exemplaryembodiment;

FIG. 11 is a top view of another exemplary embodiment;

FIG. 12 is a top view of still another exemplary embodiment; and

FIG. 13 is a side view of yet another exemplary embodiment.

DETAILED DESCRIPTION

In order to provide a more thorough understanding of the presentinvention, the following description sets forth numerous specificdetails, such as specific configurations, parameters, and the like. Itshould be recognized, however, that such description is not intended asa limitation on the scope of the present invention, but is intended toprovide a better description of exemplary embodiments.

With reference to FIG. 3, in accordance with one aspect of the presentinvention, a lid 304 can be configured to cover a section 302 of amicrotiter plate 102 having a plurality of wells 104. Accordingly, lid304 can reduce evaporation of the contents of wells 104. In addition,lid 304 can reduce the contamination of the contents of wells 104 fromthe surrounding environment and from other wells. In the exemplaryembodiment depicted in FIG. 3, lid 104 is configured to cover a section302 of a 96-well microtiter plate 102 having 16 wells arranged in 4columns and 4 rows. It should be recognized, however, that lid 104 canbe configured to cover any number of wells in any number ofconfigurations. Furthermore, lid 104 can be configured to cover wells onany type of microtiter plate or sample holder.

With reference to FIG. 5, in accordance with another aspect of thepresent invention, lid 304 can be configured to distribute fluid intowells 104. In the present embodiment, lid 304 includes a load port 306configured to receive a fluid-dispensing device. More particularly, inone configuration, load port 306 includes a threaded locking mechanism,such as a lure lock, to receive a syringe. It should be recognized,however, that load port 306 can be configured to receive variousdispensing devices, such as pipettes, pumps, automated dispensers, andthe like. Additionally, although load port 306 is depicted as protrudingfrom the surface of lid 304, it should be recognized that load port 306can be flush with respect to the surface of lid 304. Alternatively, loadport 306 can be recessed with respect to the surface of lid 304. Inaddition, it should be recognized that lid 304 can be configured withany number of load ports 306. Furthermore, each load port 306 can beconfigured to receive a different sample.

In the present embodiment, lid 304 also includes a plurality of flowchannels 402. As depicted in FIG. 5, each flow channel 402 includes afirst end connected to load port 306 and an open second end. When lid304 is positioned over a section 302 of microtiter plate 102, the secondend of flow channel 402 opens into well 104. In this manner, flowchannels 404 can be configured to distribute fluid from load port 306into wells 104.

As described above, in the present embodiment, lid 304 is configured tocover a section 302 of microtiter plate 102 having 16 wells 104 (FIG.3). As such, with reference to FIG. 4, in the present embodiment, lid304 includes 16 flow channels 402 to distribute fluid from load port 306into 16 wells 104 through flow channels 402. However, as noted earlier,lid 304 can be configured to cover any number of wells 104. Similarly,lid 304 can be configured with any number of flow channels 402 todistribute fluid into any number of wells 104. For example, lid 304 canbe configured to cover 4 wells and configured with 4 flow channels todistribute fluid to each of the 4 wells. However, lid 304 can also beconfigured to cover 4 wells and configured with 2 flow channels todistribute fluid to 2 of the 4 wells. In addition, lid 304 can beconfigured with any number of load ports 306, connected to any number offlow channels. For example, lid 306 can be configured to cover 6 wellsand configured with 2 load ports, each of which is connected to 3 flowchannels. However, lid 306 can also be configured to cover 6 wells andconfigured with 2 load ports, wherein one of the load ports is connectedto 2 flow channels and the other is connected to 3 flow channels.

In the present embodiment, the cross section of flow channels 402 isdepicted as having a circular or an oval shape. One advantage of acircular or oval shaped cross section is that the amount of fluid lostwithin flow channel 402 as the fluid passes through flow channel 402 canbe minimized. However, it should be recognized that the cross sectionsof flow channels 402 can have various shapes.

Additionally, the inner surface of flow channels 402 can be siliconizedor treated in other ways to minimize the amount of sample lost withinflow channels 402. It should be recognized, however, that for someapplications, flow channels 402 may not need to be siliconized.

Furthermore, the cross sectional size of flow channels 402 can beadjusted to accommodate the amount of pressure that the fluid-dispensingdevice can provide to move the fluid through flow channels 402. Moreparticularly, as noted earlier, various dispensing devices, such aspipettes, pumps, automated dispensers, and the like, can be used tointroduce fluid into flow channels 402. These dispensing devices canprovide different amounts of pressure to move the fluid through flowchannels 402. For example, a pump can typically provide a greater amountof pressure than a pipette. As such, a relatively larger cross sectioncan be used with a pump than a pipette. It should be recognized,however, that in some applications the fluid can flow through flowchannels 402 under capillary action rather than or in addition to beingactively pumped through flow channels 402.

With reference now to FIG. 5, flow channels 402 are depicted as havingstraight segments with square comers. One advantage of thisconfiguration is that straight segments and square comers can be formedmore easily than, for example, curved segments and rounded comers. Itshould be recognized, however, that flow channels 402 can includesegments and comers having various shapes. For example, flow channels402 can be formed with curved segments and rounded comers. One advantageof forming flow channels 402 with curved segments and rounded comers isthat the amount of fluid lost within flow channel 402 as the fluidpasses through flow channel 402 can be reduced. Additionally, as notedearlier, the cross sections of flow channels 402 can have variousshapes.

With reference to FIG. 4, flow channels 402 are depicted as extendingout from load port 306 along a curvilinear path. One advantage of thisconfiguration is that it can reduce turbulence and entrapment of air.However, it should be recognized that flow channels 402 can extend fromload port 306 along paths of various shapes. For example, flow channels402 can extend from load port 306 in straight segments with squarecorners.

With reference to FIG. 6, in the present embodiment, the second end of aflow channel 402 can include a beveled tip 602. As depicted in FIG. 6,beveled tip 602 is formed at an angle 604 with respect to the axis offlow channel 402. By adjusting angle 604, the surface area of surface606 of beveled tip 602 can be adjusted. Accordingly, the size of thedroplet formed by beveled tip 602 can be adjusted. As will be describedbelow, increasing the size of the droplet can be advantageous in drawingfluid out of flow channel 402. However, it should be recognized that thesecond end of flow channel 402 can include a straight tip.

With reference to FIG. 7, in the present embodiment, beveled tip 602 ispositioned adjacent to the side of well 104 to provide a gap 702.Additionally, beveled tip 602 is positioned such that surface 606 facesthe side of well 104. Gap 702 is selected such that a droplet emanatingfrom beveled tip 602 can contact the side of well 104. In this manner,the droplet can be drawn out of beveled tip 602 assisted, in part, bysurface tension. In a preferred embodiment, gap 702 is approximately 0.5mm. It should be recognized, however, that gap 702 can vary. Forexample, as described above, the size of the droplet formed by beveledtip 602 can be adjusted by adjusting angle 604.

Additionally, in the present embodiment, well 104 can include glassfibers that facilitate drawing fluid into well 104 from beveled tip 602.Microtiter plate 102 and wells 104 can also be siliconized to facilitatethe flow of droplets on the sides of well 104 to the bottom of well 104.However, it should be recognized that lid 304 can be used with amicrotiter plate 102 having wells 104 that do not include glass fibersand are not siliconized.

With reference to FIG. 4, in accordance with another aspect of thepresent invention, lid 304 is configured to distribute approximatelyequal amounts of fluid to wells 104 (FIG. 5). In the present embodiment,load port 306 is positioned near the center of the lid 304 to distributeapproximately equal amounts of fluid to each well 104 (FIG. 5) under lid304. Additionally, in the present embodiment, flow channels 402 haveapproximately equal lengths and approximately equal cross sectionaldiameters to distribute approximately equal amounts of fluid to eachwell 104 (FIG. 5). In a preferred embodiment, approximately 20–50 μL aredistributed to each well 104 (FIG. 5) within a tolerance of about 1 μL.It should be recognized, however, that the amount of fluid distributedto each well 104 (FIG. 5) and the acceptable tolerance can varydepending on the application.

Alternatively, it should be recognized that approximately equal amountsof fluid can be distributed to each well 104 (FIG. 5) through flowchannels 402 of different lengths by correspondingly varying the crosssectional diameters of the flow channels 402. In particular, if a firstflow channel 402 is greater in length than a second flow channel 402,then the first flow channel 402 should have a smaller cross sectionaldiameter than the second flow channel 402.

As described above and depicted in FIG. 4, in the present embodiment,load port 306 is positioned near the center of lid 304. It should berecognized, however, that load port 306 can be positioned in anylocation on lid 304. For example, load port 306 can be positioned towardone corner of lid 304. To distribute approximately equal amounts offluid from load port 306, flow channels 402 can be either formed withapproximately equal lengths and approximately equal cross sectionaldiameters, or formed with different lengths and correspondingly varyingcross sectional diameters, as described above.

In addition to distributing approximately equal amounts of fluid fromload port 306, lid 304 can be configured to distribute unequal amountsof fluid to wells 104 (FIG. 5). More particularly, if the flow channels402 have approximately equal cross sectional diameters, the relativeamount of fluid distributed to a particular well 104 (FIG. 5) can becontrolled by varying the length of the flow channel 402 to thatparticular well 104 relative to the lengths of the other flow channels402.

Additionally, it should be recognized that if the lengths of the flowchannels 402 are approximately equal, the relative amount of fluiddistributed to a particular well 104 (FIG. 5) can also be controlled byvarying the cross sectional diameter of flow channel 402 to thatparticular well 104 (FIG. 5) relative to the cross sectional diametersof the other flow channels 402.

Alternatively, the relative amount of fluid distributed to a particularwell 104 (FIG. 5) can be controlled by varying both the length and thecross sectional diameter of flow channel 402 to that particular well 104(FIG. 5) relative to the lengths and cross sectional diameters of theother flow channels 402.

With reference to FIG. 8, in another exemplary embodiment, lid 304includes rings 802. As depicted in FIG. 8, ring 802 fits within well 104to position lid 304. As described above, in the embodiment depicted inFIG. 7, beveled tip 602 is positioned adjacent the side of well 104 toprovide gap 702. With reference again to FIG. 8, rings 802 canfacilitate the proper positioning of lid 304 to provide for gap 702(FIG. 7). It should be recognized that lid 304 need not include a ring802 for every well 104 covered by lid 304 to position lid 304. Forexample, if lid 304 covers 16 wells arranged in 4 rows and 4 columns,lid 304 can include a ring 802 on two of the comers.

Additionally, it should be recognized that ring 802 need not be formedas a ring. For example, rings 802 can be formed as a plurality of tabsthat extend into well 104. However, in some applications, rings 802 canbe used to seal each well 104. In such applications, lid 304 can includea ring 802 for every well 104 to be sealed. Additionally, in suchapplications, rings 802 can be formed as an enclosed ring. It should berecognized, however, that the shape of rings 802 can depend on the shapeof wells 104 and the particular application.

As depicted in FIG. 9, in the present embodiment, ring 802 engages withthe side of well 104 to secure lid 304 onto microtiter plate 102. Itshould be recognized, however, that lid 304 can be secured to microtiterplate 102 using other attachment mechanisms, such as teeth, latches,adhesives, and the like. Additionally, lid 304 and microtiter plate 102can be fused together, such as by melting at least a portion of eitherone or both of the lid 304 and microtiter plate 102.

Microtiter plate 102 can also be configured to engage with lid 304. Forexample, with reference to FIG. 10, microtiter plate 102 can includewells 104 with ridges 1004 and lid 304 can include matching channels1002.

In some applications, lid 304 can be configured to form an air-type sealwith microtiter plate 102. More particularly, in some applications, thesection covered by lid 304 can be sealed with an air-tight seal, such aswith an appropriate gasket, adhesive, and the like. In someapplications, each individual well 104 can be sealed with an air-tightseal, such as with an appropriate gasket, adhesive, and the like.

Additionally, with reference to FIG. 5, load port 306 can include acover 308. In some applications, cover 308 can also be configured toform an air-tight seal with load port 306. For example, a gasket can beused to form an air-tight seal between cover 308 and load port 306.However, it should be recognized that in some applications cover 308 canbe omitted.

In accordance with another aspect of the present invention, lid 304 canbe formed as two pieces joined together. Flow channels 402 can be formedby etching or molding portions of their cross-sectional profiles intothe opposing surfaces that are joined together. Alternatively, one pieceof lid 304 can be molded or etched with flow channels 402 then joined toa flat second piece. It should be recognized, however, that lid 304 andflow channels 402 can be formed using various methods. For example, lid304 can be molded as a single piece with flow channels 402 formed withinthe mold. Alternatively, flow channels 402 can be formed or attached tothe surfaces of lid 304.

Additionally, lid 304 can be constructed of various materials dependingon the application. For example, lid 304 can be constructed of abiologically inert plastic that does not interfere with tests,reactions, assays, and the like in biology, chemistry, clinicaldiagnostics, and other areas in which the lid 304 may be used. Lid 304can be formed from material that can withstand exposure to a range oftemperatures without exhibiting any change in characteristics that wouldinterfere with tests, reactions, assays, and the like in which lid 304may be used. For instance, if lid 304 is used in conjunction with apolymerase chain reaction (PCR) assay, lid 304 can be constructed ofmaterials that can withstand at least a range of temperatures betweenabout 4° C. and about 98° C. See, e.g., James D. Watson et al., SecondEdition: Recombinant DNA 82 (1992). However, it should be recognizedthat lid 304 can be constructed of materials that are not biologicallyinert or thermally resistant.

In some applications, lid 304 can be constructed of various materialshaving different thermal resistances, such that portions of lid 304 meltat a certain temperature, while other portions of lid 304 do not melt atthis temperature. For example, with reference to FIG. 8, flow channel402 depicted to the left of load port 306 can be constructed of amaterial that melts at a first temperature, while the rest of lid 304 isconstructed of a material that melts at a second temperature, which ishigher than the first temperature. When lid 304 is heated to the firsttemperature, flow channel 402 depicted to the left of load port 306 canmelt shut, such that a sample cannot flow through it. At the same time,flow channel 402 depicted to the right of load port 306 is unaffected.In this manner, the number of active flow channels in lid 304 can bealtered. It should be noted that lid 304 can be constructed of anynumber of different materials, such that heating lid 304 to differenttemperatures alters the number of active flow channels 402. Forinstance, lid 304 can be constructed of various materials, such thatheating lid 304 to a first temperature inactivates two flow channels,further heating lid 304 to a second temperature greater than the firsttemperature inactivates two additional flow channels, and so forth.

In some applications, lid 304 can be constructed of materials that donot interfere with post amplification analysis of PCR products. Forexample, if lid 304 is used with a fluorescence detection system, lid304 can be constructed of materials that have low levels of fluorescenceand that do not autofluoresce if exposed to UV light, such as apolyethylene plastic that does not autofluoresce. In addition, lid 304can be constructed of a material having sufficient optical clarity toallow lid 304 to be used with a fluorescence detection system withoutinterfering with the analysis.

If lid 304 is used with an Enzyme-Linked Immunosorbent Assay (ELISA)plate reader, lid 304 can be constructed of materials that do notinterfere with the efficiency of this detection system. For example, ifthe ELISA plate reader is used in conjunction with absorbance orcolorimetric detection methods, lid 304 can be constructed of materialsthat minimize interference with the efficiency of these methods. Lid 304can also be constructed of a material having sufficient optical clarityto allow lid 304 to be used with an ELISA plate reader withoutinterfering with the analysis, such as polystyrene.

With reference to FIG. 11, in accordance with another aspect of thepresent invention, multiple lids 304 can be combined to formmultisection lid 1104 and utilized to cover multiple sections 302 ofmicrotiter plate 102 (FIG. 3). Each of the two lids 304 includes a loadport 306 configured to distribute fluid to wells 104 (FIG. 3) in asection 302 of the microtiter plate 102 (FIG. 3). As such, each loadport 306 can be used to distribute a different fluid to the differentsections 302 of microtiter plate 102 (FIG. 3). Multisection lid 1104 canbe formed as a single unit, two lids 304 that are connected together atjoints 1102 by any convenient method, or as two lids 304 that areadjacent but not connected.

As described above, in the present embodiment, lid 304 can be configuredto cover a section 302 of microtiter plate 102 (FIG. 3) having 16 wellsarranged in 4 rows and 4 columns. Additionally, with reference to FIG.1, in one exemplary application of the present invention, lid 304 can beused in connection with a microtiter plate 102 with 96 wells arranged in8 rows and 12 columns. With reference to FIG. 12, 6 lids 304 can bearranged to partition microtiter plate 102 into 6 sections. In thismanner, fluid can be introduced into the 96 wells of microtiter plate102 through the 6 load ports 306 of lids 304. Additionally, differentfluids can be introduced into each section of microtiter plate 102.

As noted earlier, it should be recognized that microtiter plate 102 caninclude any number of wells arranged in various configurations.Additionally, lid 304 can cover any number of wells in variousconfigurations. Furthermore, it should be recognized that lid 304 can beused with various types of sample holders. For example, with referenceto FIG. 13, lid 304 can be used with sample holder 1302, which includestray 1306 having vials 1304.

Having thus described various embodiments of lid 304, the followingdescription will relate to the use of the lid 304 for PCR assays, whichcan be used to detect the presence of a particular DNA sequence in asample. It should be recognized, however, that lid 304 can be used inperforming various tests, reactions, assays, and the like in biology,chemistry, clinical diagnostics, and other areas.

In general, PCR can be used to amplify samples of DNA by repeatedlyheating and cooling a mixture containing DNA, an oligonucleotide primer,an assortment of all four deoxyribonucleic precursors, DNA polymerase,and, when appropriate, a buffer. The mixture is first heated totemperatures sufficient to separate DNA strands. The mixture is thencooled to temperatures appropriate to allow primers to bind to the DNAstrands. The mixture is then reheated to temperatures sufficient toallow the polymerase to synthesize new DNA strands by binding theprecursors to appropriate locations on the separated DNA strands. Theprocess can be repeated in order to double the concentration of the DNAsample in each cycle. Successful amplification of the DNA samples can bedetected by fluorescence, absorbance, or colorimetric methods, using,for instance, a fluorescence detection system or ELISA plate reader, asappropriate.

In one exemplary application, lid 304 and microtiter plate 102 can beused to perform a PCR assay to test for hepatitis. As described above,with reference to FIG. 12, multiple lids 304 can be used to partitionmicrotiter plate 102 (FIG. 1) into multiple sections 302 (FIG. 3). Eachsection 302 (FIG. 3) can be used to test a sample from a single patient.Accordingly, samples from different patients can be tested using asingle microtiter plate 102.

With reference to FIG. 1, in one exemplary application, before usinglids 304, each well 104 of a microtiter plate 102 can be pre-loaded witha diagnostic substance that contain the components for a PCR reaction,except a sample from a patient, such that each section 302 of themicrotiter plate 102 has wells 104 containing diagnostic substances fortesting hepatitis A, B, and/or C, including diagnostic substances thatcan be used as controls or negative controls. The diagnostic substancescan be lyophilized and stuck to the bottom of each well where they arechemically stable and unable to move.

As depicted in FIG. 12, 6 lids 304 can then be used to partition themicrotiter plate 102 (FIG. 1) into 6 sections 302 (FIG. 3) with 16 wellsin each section 302. Plate 102 covered with lids 304 can now be used totest samples from patients.

A different sample of DNA is distributed to each section 302 ofmicrotiter plate 102 (FIG. 3) through each load port 106. Aftermicrotiter plate 102 (FIG. 3) is exposed to the heating and coolingcycles of the PCR, the samples of DNA should be amplified in wells 104(FIG. 3) of microtiter plate 102 (FIG. 3) that would yield a positiveresult. For instance, if the 6 samples correspond to 6 different people,then if all 6 people have hepatitis A, then the DNA in wells 104 (FIG.3) containing the diagnostic substance for hepatitis A in each section302 (FIG. 3) of the microtiter plate 102 (FIG. 3) should be amplified.

Accordingly, in this manner, a screen test for hepatitis A, B, and/or Ccan be performed on 6 different samples that correspond to 6 differentpeople, within a single microtiter plate 102. Additionally, 16 tests canbe conducted for a single person by loading a DNA sample from thisperson into a single load port 306 and thereby distributing the DNAsample to each of 16 wells 104 containing different diagnosticsubstances, respectively. In comparison, a manual process for loadingeach of the wells 104 with a sample would have been more labor intensiveand time consuming, and an automated process for loading each wellindividually can be more costly.

Additionally, lids 304 can reduce contamination between wells in asection, between sections in microtiter plate 102, and betweenmicrotiter plate 102 and the surrounding environment. Lids 304 can alsoreduce evaporation and condensation of substances in wells 104 (FIG. 1).In addition, lids 304 can contain samples within the wells of microtiterplate 102 and minimize human exposure to the samples within the wells.

Although the present invention has been described with respect tocertain embodiments, configurations, examples, and applications, it willbe apparent to those skilled in the art that various modifications andchanges may be made without departing from the invention.

1. A lid for a sample holder, the sample holder having a plurality ofreservoirs, the lid comprising: a load port configured to receive avolume of fluid; and a plurality of flow channels; wherein each saidflow channel has a length and a cross-sectional diameter, a first endconnected to said load port, and a second end that opens into a singlereservoir of said plurality of reservoirs when the lid covers the sampleholder, and wherein when the volume of fluid is received in the loadport, the respective lengths and cross-sectional diameters of theplurality of flow channels are the same or different as required todistribute the volume of fluid received in the load port inapproximately equal amounts to each reservoir of the plurality ofreservoirs.
 2. The lid of claim 1, wherein at least a first flow channeland a second flow channel of said plurality of flow channels have equallengths.
 3. The lid of claim 2, wherein said load port is disposed atthe center of the lid.
 4. The lid of claim 1, wherein said load port isconfigured to interface with a fluid-dispensing device.
 5. The lid ofclaim 4, wherein said fluid-dispensing device is a syringe.
 6. The lidof claim 5, wherein said load port includes a threaded lockingmechanism.
 7. The lid of claim 4, wherein said fluid-dispensing deviceis a pipette.
 8. The lid of claim 1, wherein each said flow channel issiliconized.
 9. The lid of claim 1, wherein each said flow channel isconfigured to allow fluid to pass from said first end to said second endof each said flow channel by pressure.
 10. The lid of claim 1, whereineach said flow channel is configured to allow fluid to pass from saidfirst end to said second end of each said flow channel by capillaryaction.
 11. The lid of claim 1, wherein each said flow channel isconfigured to allow fluid to passively flow from said first end to saidsecond end of each said flow channel.
 12. The lid of claim 1, wherein afirst flow channel of said plurality of flow channels includes at leastone curved segment.
 13. The lid of claim 1, wherein a first flow channelof said plurality of flow channels includes at least one straightsegment.
 14. The lid of claim 1, wherein the second end of a first flowchannel of said plurality of flow channels ends in a beveled tip. 15.The lid of claim 1, wherein the second end of a first flow channel ofsaid plurality of flow channels is positioned at a distance from asurface of a first reservoir of said plurality of reservoirs when thelid covers the sample holder, and wherein said distance allows fluidfrom said second end to contact the surface to draw the fluid from saidsecond end by surface tension.
 16. The lid of claim 15, wherein saiddistance is about 0.5 mm.
 17. The lid of claim 1, wherein the lid isremovably attached to a section of the sample holder by an attachmentmechanism.
 18. The lid of claim 17, wherein said attachment mechanismforms an air-tight seal between the lid and said section.
 19. The lid ofclaim 1, wherein the lid is fixed to a section of the sample holder byan attachment mechanism.
 20. The lid of claim 19, wherein saidattachment mechanism forms an air-tight seal between the lid and saidsection.
 21. The lid of claim 1, wherein the lid is fused to the sampleholder.
 22. The lid of claim 1, further comprising a ring disposed nearthe second end of a first flow channel of said plurality of flowchannels.
 23. The lid of claim 22, wherein said ring positions saidsecond end of said first flow channel with respect to a first reservoir.24. The lid of claim 23, wherein said ring allows the lid to enclose thefirst reservoir.
 25. The lid of claim 24, wherein said ring forms anair-tight seal between the lid and the first reservoir.
 26. The lid ofclaim 1, wherein said load port includes a removable cover.
 27. The lidof claim 26, wherein said cover forms an air-tight seal with said loadport.
 28. The lid of claim 1, wherein a first flow channel of saidplurality of flow channels is formed of a material having a differentthermal resistance than a second flow channel of said plurality of flowchannels.
 29. A lid for a sample holder comprising: a load port disposedon the lid, wherein the load port is configured to receive a volume offluid; a plurality of flow channels formed within the lid, wherein eachsaid flow channel has a length and a cross-sectional diameter, whereineach said flow channel has a first end connected to said load port andan open second end; wherein said second ends of each said flow channelopen into a single reservoir of a plurality of reservoirs in the sampleholder when the lid covers the sample holder, and wherein when thevolume of fluid is received in the load port, the respective lengths andcross-sectional diameters of the plurality of flow channels are the sameor different as required to distribute the volume of fluid received inthe load port in approximately equal amounts to each said reservoir ofthe plurality of reservoirs.
 30. The lid of claim 29, wherein at least afirst flow channel and a second flow channel of said plurality of flowchannels have equal lengths.
 31. The lid of claim 30, wherein said loadport is disposed at the center of the lid.
 32. The lid of claim 29,wherein said load port is configured to interface with a fluiddispensing device.
 33. The lid of claim 29, wherein each said flowchannel is siliconized.
 34. The lid of claim 29, wherein each said flowchannel is configured to allow fluid to pass from said first end to saidsecond end of each said flow channel by pressure.
 35. The lid of claim29, wherein each said flow channel is configured to allow fluid to passfrom said first end to said second end of each said flow channel bycapillary action.
 36. The lid of claim 29, wherein each said flowchannel is configured to allow fluid to passively flow from said firstend to said second end of each said flow channel.
 37. The lid of claim29, wherein a first flow channel of said plurality of flow channelsincludes at least one curved segment.
 38. The lid of claim 29, wherein afirst flow channel of said plurality of flow channels includes at leastone straight segment.
 39. The lid of claim 29, wherein the second end ofa first flow channel of said plurality of flow channels ends in abeveled tip.
 40. The lid of claim 29, wherein the second end of a firstflow channel of said plurality of flow channels is positioned at adistance from a surface of a first reservoir of said plurality ofreservoirs when the lid covers the sample holder, and wherein saiddistance allows fluid from said second end to contact the surface todraw the fluid from said second end by surface tension.
 41. The lid ofclaim 40, wherein said distance is about 0.5 mm.
 42. A method ofdistributing a volume of fluid into a plurality of reservoirs of asample holder comprising: positioning a fluid-dispensing device withrespect to a load port formed on a lid, wherein the load port isconfigured to receive a volume of liquid and wherein said lid includes aplurality of flow channels, each said flow channel having a first endconnected to said load port and an open second end, wherein each saidflow channel has a length and a cross-sectional diameter, andintroducing the volume of fluid into said load port with saidfluid-dispensing device, wherein the respective lengths andcross-sectional diameters of the plurality of flow channels are the sameor different as required to distribute the volume of fluid received inthe load port in approximately equal amounts to each reservoir of theplurality of reservoirs.
 43. The method of claim 42, wherein thefluid-dispensing device is a syringe.
 44. The method of claim 42,wherein the fluid-dispensing device is a pipette.
 45. The method ofclaim 42, wherein said positioning further comprises engaging saidfluid-dispensing device with a threaded locking mechanism in said loadport.
 46. The method of claim 42, wherein at least a first flow channeland a second flow channel of said plurality of flow channels have equallengths.
 47. The method of claim 42, wherein said load port is disposedat the center of the lid.
 48. A lid for a sample holder, the sampleholder having a plurality of reservoirs, the lid comprising: a load portconfigured to receive a volume of fluid; and a plurality of flowchannels; wherein the lid is in fluid communication from the load portto the respective reservoirs via the respective flow channels; whereinthe flow channels have (i) approximately equal lengths and approximatelyequal cross-sectional diameters, or (ii) differing lengths ofcorrespondingly varying cross-sectional diameters such that the volumeof fluid distributed to each reservoir is approximately equal; andwherein the second ends of the respective flow channels are positionedsuch that a droplet emanating therefrom contacts a side of therespective reservoirs.
 49. The lid of claim 48, wherein at least oneflow channel has a cross-sectional diameter that differs from that ofthe other flow channels.
 50. The lid of claim 48, wherein the pluralityof flow channels each have an approximately equal length andapproximately equal cross-sectional diameter.
 51. The lid of claim 48,wherein the plurality of flow channels includes at least one flowchannel that, relative to one other flow channel, has a differing lengthand a correspondingly varying cross-sectional diameter.